Ask question

Ask question

All categories

3 years ago

13

Calculate the amount of heat (kcal) released when 50.0g of steam at 100*c hits the skin, condenses, and cools to a body temperat

ure of 37*c

2 answers:

abruzzese [7]3 years ago

7 0

conversion of steam at 100 C to water at 100 C :

m = mass of the steam = 50 g

L = latent heat of condensation of steam to water = 79.7 J/g

Heat released in conversion of steam to water is given as

Q₁ = mL

inserting the values

Q₁ = (50) (79.7)

Q₁ = 3985 cal

conversion of water at 100 C to water at 37 C :

ΔT = change in temperature = 100 - 37 = 63 C

c = specific heat of water = 1 cal/(gC)

m = mass of water = 50 g

Heat released in change of temperature is given as

Q₂ = m c ΔT

Q₂ = 50 x 1 x 63

Q₂ = 3150 cal

total heat released is given as

Q = Q₁ + Q₂

Q = 3985 + 3150

Q = 7135 cal

luda_lava [24]3 years ago

6 0

As the steam touches the skin, it undergoes a phase change and releases latent heat due to the phase change. As it reaches equilibrium, it releases sensible heat. We calculate as follows:

Q = latent heat + sensible Heat
Q = 2.26 kJ / g (50.0 g) + 50.0 g ( 4.18 J / g C) (37 C - 100 C) ( 1 kJ / 1000 J)
Q = 99.833 kJ

You might be interested in

ss7ja [257]

<em><u>QB=-8×10^-9C.</u></em>
<em><u>QB=-8×10^-9C.We fixed balls A and B 5cm apart. Given e=1.6×10^-9C and k=9×10^9 S.I unit.</u></em>

4 0

3 years ago

Determine the CM of a rod assuming its linear mass density λ (its mass per unit length) varies linearly from λ = λ0 at the left

Dahasolnce [82]

Answer:

$x_c= \dfrac{5}{9}L$

$I=\dfrac {7}{12}\lambda_ 0 L^3$

Explanation:

Here mass density of rod is varying so we have to use the concept of integration to find mass and location of center of mass.

At any distance x from point A mass density

$\lambda =\lambda_0+ \dfrac{2\lambda _o-\lambda _o}{L}x$

$\lambda =\lambda_0+ \dfrac{\lambda _o}{L}x$

Lets take element mass at distance x

dm =λ dx

mass moment of inertia

$dI=\lambda x^2dx$

So total moment of inertia

$I=\int_{0}^{L}\lambda x^2dx$

By putting the values

$I=\int_{0}^{L}\lambda_ ox+ \dfrac{\lambda _o}{L}x^3 dx$

By integrating above we can find that

$I=\dfrac {7}{12}\lambda_ 0 L^3$

Now to find location of center mass

$x_c = \dfrac{\int xdm}{dm}$

$x_c = \dfrac{\int_{0}^{L} \lambda_ 0(1+\dfrac{x}{L})xdx}{\int_{0}^{L} \lambda_0(1+\dfrac{x}{L})}$

Now by integrating the above

$x_c=\dfrac{\dfrac{L^2}{2}+\dfrac{L^3}{3L}}{L+\dfrac{L^2}{2L}}$

$x_c= \dfrac{5}{9}L$

So mass moment of inertia $I=\dfrac {7}{12}\lambda_ 0 L^3$ and location of center of mass $x_c= \dfrac{5}{9}L$

8 0

3 years ago

Please. Physics is so difficult.

Softa [21]

Answer:

0.010 m

Explanation:

So the equation for a pendulum period is: $y=2\pi\sqrt{\frac{L}{g}}$ where L is the length of the pendulum. In this case I'll use the approximation of pi as 3.14, and g=9.8 m\s. So given that it oscillates once every 1.99 seconds. you have the equation:

$1.99 s = 2(3.14)\sqrt{\frac{L}{9.8 m\backslash s^2}}\\$

Evaluate the multiplication in front

$1.99 s = 6.28\sqrt{\frac{L}{9.8m\backslash s^2}$

Divide both sides by 6.28

$0.317 s= \sqrt{\frac{L}{9.8 m\backslash s^2}}$

Square both sides

$0.100 s^2= \frac{L}{9.8 m\backslash s^2}$

Multiply both sides by m/s^2 (the s^2 will cancel out)

$0.984 m = L$

Now now let's find the length when it's two seconds

$2.00 s = 6.28\sqrt{\frac{L}{9.8m\backslash s^2}}$

Divide both sides by 6.28

$0.318 s = \sqrt{\frac{L}{9.8 m\backslash s^2}$

Square both sides

$0.101 s^2 = \frac{L}{9.8 m\backslash s^2}$

Multiply both sides by 9.8 m/s^2 (s^2 will cancel out)

$0.994 m = L$

So to find the difference you simply subtract

0.984 - 0.994 = 0.010 m

4 0

2 years ago

Read 2 more answers

What is potential difference also called?

malfutka [58]

Voltage - V = IR : v= voltage i= current r= resistance

6 0

3 years ago

Which factors are used to calculate the kinetic energy of an object? Check all that apply. gravity velocity volume mass height

Sonja [21]

<em>Quantities that determine the kinetic energy of a body are its </em><em>mass and velocity </em>

Answer: <em>mass and velocity </em>

Explanation:

The kinetic energy of a body is the energy possessed by an object by virtue of its motion. It is given by the equation

$k= \frac{1}{2}mv^2$

Where m represents mass of the body and v represents its velocity.

Two bodies of equal velocity but different mass the heavier body will have greater kinetic energy. When an object is at rest its velocity is equal to zero. Thus its kinetic energy will be zero. Hence it can be concluded that only moving bodies have kinetic energy.

Stationary objects placed at a height possess potential energy which is the energy by virtue of their position or configuration. The total mechanical energy of a system is the sum of potential and kinetic energy.

8 0

3 years ago

Read 2 more answers